This application claims the priority of Korean Patent Application No. 2003-42134, filed on Jun. 26, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a wobble detection system used in an optical disc apparatus such as a DVD+R/RW disk, and more particularly, to a circuit for detecting an ADIP (address in pre-groove) signal in a wobble detection system and a method for detecting an ADIP signal.
2. Description of the Related Art
To record data on a DVD+R/RW disk, it is critical that the disc address information, that is, ADIP (address in pre-groove) of the DVD+R/RW disk, is correctly demodulated. In a case where the disc address information is not correctly demodulated, recording quality is reduced and it may be impossible to read data recorded on the DVD+R/RW disk.
The ADIP signal of a DVD+R/RW disc has discontinuous points, unlike an ATIP (Absolute Time In Pre-groove) signal of a CD, as shown in FIG. 1. Since these discontinuous points represent data of an ADIP unit according to ADIP Modulation Rules, it is very important to detect the discontinuous points.
FIG. 2 is a block diagram of a wobble detection system used in a conventional DVD+R/RW disc system. Referring to FIG. 2, a wobble detection circuit 22 receives a signal from an OPU (Optical Pick-up Unit) 21, detects a wobble signal WB from the received signal, and transfers the WB signal to an ADIP signal detection circuit 23. The ADIP signal detection circuit 23 receives the wobble signal WB, detects an ADIP signal ADIP, and transfers the ADIP signal ADIP to an ADIP decoder 24. The ADIP decoder 24 decodes the ADIP signal ADIP.
However, as described above, since the ADIP signal has discontinuous points, it is necessary that the ADIP signal detection circuit 23 detects the discontinuous points correctly and quickly. Also, the ADIP signal detection circuit 23 should have a simple configuration to be easily implemented.